Built-up roofing



A. HARRIS.

BUILT-UP ROOFING.

APPLICATION FILED 00121v ms.

Patented Aug. 29,1922.

' UNITED STATES PATENT OFFICE.

WILLIAM A. HARRIS, OF BROOKLINE, MASSACHUSETTS, ASSIGNOR TO THE FLINT- KOTE COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MASSACHU- SETTS.

BUILT-UP ROOFING.

To all whom it may concern Be it known that I, VILLIAM A. HARRIS, a citizen of the United States, residing at Brookline, in the county of Norfolk and State of Massachusetts, have invented new and useful Improvements in BuiltfiUp Roofing, of which the following is a specification.

This invention has for its object to provide certain improvements in roofs and in the method of producing the same.

The roof consists of a supporting structure of boards or sheathing or the equivalent, and a covering of prepared roofing sheets lapping one upon the other and cemented together, the exposed portions only of the sheets being formed or provided with relatively thick layers of crushed mineral, such as slate, grit or the like, embedded therein.

On the drawing,-

Figure 1 shows a portion of a completed roof and illustrates the method of forming it. v

Figure 2 illustrates a sloping roof embodying the invention.

Figure 3 represents a transverse section through the covering.

Figure 4 is a diagrammatic view illustrating how the sheets are laid.

Figure 5 illustrates a section on the line 5-5 of Figure 3.

Figure 6 represents a section through a roof covering in which the under side of the sheet, beneath the uncovered zone thereof, is reinforced.

Figure 7 represents a cross section through one of the sheets in Figure 6.

The roof support may be slightly pitched as in Figure 1, or fiat, orpitched at a sharp angle as in Figure 2, or otherwise formed as architecturally desirable. On the usual supporting beams or rafters (not shown) is the deck or support 10, consisting, if desired, of 'plain or matched boards, upon which the covering is laid and securedv Usually, beginning at the lower edge of the roof, parallel to the eaves, adjacent to the gutter flashing 12. I place a'strip 13 of saturated but uncoated felt, running the length of the support 10, but approximately seventeen inches wide, or about half the width of a sheet of roofing. This strip consists of a suitable fibrous foundation, such as asbes- Specifica tion of Letters Patent. Patented Aug. 29, 1922.

Application filed October 21, 1918.

Serial No. 259,090.

tosor rag felt waterproofed by its impregnation with asphalt or other usual hydrocarbon Waterproofing compound; and it is secured in place by a line of fasteners 14 driven through its lower edge into the rafters and another line of fasteners 15. If there is a metal gutter flange, it is coated w th molten asphalt before the strip is applied, and in fact the gutter flange 12 may be likewise coated before the application of the sheet. After the first felt strip is thus secured in place the remainder of the support may now be covered. If the roof is flat, while the overlapping sheets may be laid parallel to the eaves strip 13 as shown in Figure 1, thesheets are preferably laid at a right angle thereto as shown in Figure 2.

The sheets each consist of a body a or foundation of felt or equivalent material, saturated and impregnated with asphaltor other equivalent compound of relatively low melting point. Upon the saturated sheet, so as. to cover less than one-half the width thereof, is a layer 6 of higher-melting-point pitch or asphalt, in which is partially embedded a thick layer 0 of crushed mineral of an ornamental nature, the sheets being thus produced. or fabricated at the factory. Each sheet has therefore one lengthwise stripe or zone of asphalt coatingand a crushedmineral layer embedded more or less therein, and one parallel uncoated v stripe. This uncoated stripe or zone of the sheet has had the surplus impregnating material squeezed therefrom, and has a rough dry exterior surface. Assuming each sheet to be thirty-two inches in width, the un coated zone would preferably be seventeen inches in width, and the coated and mineralsurfaced zone fifteen inches in width. These relative proportions may be preserved in sheets of greater or less width.

Assuming that the sheets are to be laid parallel to the eaves strip 13, the latter is first coated with a layer 17 of anadhesive mate rial, preferably blown asphalt or pitch, having a melting point of 200 F. or higher, while it is in a molten, liquid or plastic or adhesive state. Then the sheet 16 of the roofing material is placed on and rolled upon the layer 17 of asphalt'or pitch, so that the mineral-surfaced zone is above said strip 13, as shown in Figures 1 and 3,

Thereupon nails 18 are driven through the uifcoated zone into the support 10, and such uncoated zone is coated with a layer 19 of said waterproof adhesive, and the next sheet 20 is laid thereon as shown in said lastmentioned figures. The sheets are thus laid until the roof is covered. In the case of a pitch roof, a ridge strip 21 may be cemented inplace if desired, as shown in Figure 2. Each sheet overlaps a distance of seventeen inches upon the preceding strip, so that the outer edge of the sheet abuts the shoulder 25 formed at the inner edge of the layers of asphalt and mineral-surfacing material, on said preceding sheet, and thus the mineral surface is continuous over the whole roof, when all of the strips have been secured in place. The under surface of substantially one-half of each sheet is permanently united by a layer of asphalt to the next sheet, which it overlaps, and the upper surface of substantially the other half is likewise united to the adjacent sheet which overlaps it. At any one point on the roof there are at least five layers, as shown by the section in Figure 5, namely, a layer a of saturated felt, a layer 19 of pitch or asphalt, a layer of saturated felt, a layer 5 of asphalt or pitch, and a layer 0 ofcrushed mineral or grit of suitable character. The

- covering for the support 10 consists finally 'of a practically integral sheet of large area comprising deeply overlapping strips, each of which is secured to the support, and each of which is permanently united to the two next adjacent strips by asphalt or pitch; and, since the latter is applied in molten condition to the saturated but uncoated surfaces of the felt, the fibers interlock therewith and each two adjacent sheets are firmly united.

In laying the sheets upon a peaked roof, they may extend from the eaves to the ridge. the lower ends being united to the eaves strip by the bituminous compound. In lieu of a wooden board support, I may use one made of cement concrete; in which case, in lieu of nails, the sheets may be fastened by coating the concrete with molten pitch or asphalt, and laying the sheets thereon while the compound is liquid or adhesive. If desired, the support may have initially applied thereto a layer of asphalt saturated felt or paper tacked or cemented in place, upon which the roof covering herein described may be laid and secured. In case the roof is enclosed in walls, as in Figure 1, the sheets may be bent upwardly and cemented to the walls by the application of hot pitch or asphalt, and a counter flashing, lapped downwardly over the upturned sheets,- may be employed.

it is not necessary that the under face of the sheet should be uncoated, and in Figure 7 I have shown conventionally a sheet which may, with others, be laid as in Figure 6 to form a built-up roof covering. This sheet is like that hereinbefore described, except that on its under or lower face it is reinforced beneath a portion of the uncoated zone of the top face. That is, from the edge inward, the under face has a zone fifteen inches wide which is coated with a layer of asphalt 23 and a surface layer 24 of grit or sheet asbestos. Between the inner edges of the coated zone on the upper face and the coated zone on the lower face, the felt foundation has a middle portion or zone 00 which is coated on neither face.

I do not specifically claim as my invention the described sheet per se, but have illustrated and explained it as an element which may be used in the constructionof a built-up roof embodying my invention. These sheets are laid in the manner previously described, the adhesive molten asphalt being applied to the uncoated zone of the upper side or face of each sheet, and the coated zone on the lower side or face of the next succeeding sheet being pressed into contact therewith. If the surface layer on the under side of the sheet be either asbestos or'grit, it will be interlocked with the overlapped sheet by the intervening layer of asphalt.

It is generally recognized that a substantial mineral covering is quite desirable from the standpoint of fire protection. In the tar or pitch and gravel or slag roof, it is required that approximately four hundred pounds of gravel or three hundred pounds of slag be applied per hundred square feet. It is necessary to bring this material to the job in wagons and to apply it by means of shovels over the top dressing of liquid tar v or pitch. The method of the application of this mineral surfacing is quite crude, resulting, if the roof slope amounts to -anything, or if the roof surface is subjected to any considerable flow of water, in the washing of a considerable portion of this surfacing material into the gutters and eventually clogging them. The tar has the disadvantage of a relatively low melting point, so that not infrequently, in very hot weather, one may find tar oozing from the ground outlet of the downspout, this tar having run off into the gutters, and from the gutters into the downspout.

A built-up roofing, as herein described, possesses a distinct labor saving advantage .in the fact that the top layer of asphalt is applied by machinery at the factory, that the mineral surfacing is also applied to this top layer by machinery, and that consequently in the application of this roofing the operations entailed in the application of the top dressing of asphalt and ofthe mineral surfacing are eliminated. Also, this mineral surfacing, if of slate, is in the nature of flakes or laminations; hence it readily covers the entire surface of the asphalt coating. There is practically no loose or surplus mineral surfacing, as is certain to be the case when a coarse mineral surfacing, consisting largely of sand, pebbles or round stones, is applied upon a comparatively fiat surface. The result is a more uniform top dressing of asphalt and a much more uniform and lighter weight mineral surfacing, which comparatively speaking is not subject to washing away, and at the same time this roof fulfills all the essential requirements of a satisfactory built-up roofing. It is practically like a monolithic roof in character. While the slate surfacing is light in weight and small in volume, it is quite fire-retardant and furnishes an excellent surface on which to walk.

surface a longitudinal zone, less than onehalf the width of the sheet, covered with asphalt, and a layer of crushed mineral adherent thereto and terminating with an inner shoulder longitudinal of the sheet, and a parallel unsurfaced zone extending from the edge of the sheet to said shoulder; securing that part of the sheet having the uncoated zone to the roof support by fasteners passing through an uncoated portion of the sheet overlaid thereb applying a layer of plastic asphalt to't e surface of each uncoated zone; lapping the top-surfaced 'portion of each sheet upon the plastic asphalt on the freshly coated portion of the preceding sheet, with the edge of the top-surfaced zone of each sheet abutting the inner shouldered edge of the top-surfaced zone of the preceding sheet; and pressing said overlapping sheets together and permitting the asp alt to set, whereby the whole roof covering constitutes a single sheet secured b concealed fasteners and having its exposed ace covered and protected by the crushed mineral, substantially as described.

In testimony whereof I have aflixed my signature.

WILLIAM A. HARRIS. I 

